An electronic component mounting line which mounts electronic components onto a board is configured by coupling a plurality of electronic component mounting apparatuses to each other. A board onto which mounting is to be performed passes through the electronic component mounting apparatuses from upstream side to the downstream side, so that electronic components are sequentially mounted onto the board. The board onto which components have been mounted is sent to a reflow apparatus in order to be subjected to solder bonding. Depending on the kind of the board, in advance of the solder bonding, it is necessary to perform an appearance check on the board onto which components have been mounted. The appearance check is performed by taking an image of the electronic components on the board. In the case where the upper sides of already mounted components are covered by a shield case, stack components, or the like and then new electronic components are to be mounted, therefore, an appearance check against the already mounted components must be performed before the mounting of the new electronic components.
In the case where electronic components which are essentially required to be subjected to an appearance check exist in the electronic components to be covered by a shield case, stack components, or the like, therefore, a checking apparatus for an appearance check is placed upstream from an electronic component mounting apparatus which mounts these components (see Patent Reference 1). The prior art example shown in the Patent Reference has a configuration where the checking apparatus MC is placed upstream from the electronic component mounting apparatus MD which mounts a shield case.